Can a soil pipe be vented like this?

[tomsim]

View media item 36049

 

[tomsim]

Can I not just cap that 3 inch pipe after it has picked up the bath and basin waste. Thanks again for your help..

 

[Richard C]

That’s how I envisaged it but which is the bath & which is the basin?

Can I not just cap that 3 inch pipe after it has picked up the bath and basin waste.

I’m not sure I understand what you mean; yes you can cap the 3” pipe (are you sure it’s 3”?) but only if you fit a Hepvo valve;
http://www.onplumb.com/32mm-hepvo-self-sealing-waste-valve-bv.html
to the basin waste (probably).

Otherwise you need to extend the 3” pipe above the highest flood point (the wash basin) & fit an AAAV to the top;
http://www.screwfix.com/p/floplast-air-admittance-valve-32-x-40-x-50mm/42968

If you just cap the pipe off you will start siphoning the basin trap & be back to square one

 

[tomsim]

Thanks for the advise. Why would it need another vent though. I thought one was ok at the top of the stack? Yh its 3inch 82mm so is a funny size to get a fitting for.

 

[Nige F]

If you just cap the pipe off you will start siphoning the basin trap & be back to square one

Bet it won`t - not dropping into a 3 inch - it`s not correct - but I`ll lay £5 it don`t syphon - if it does the £5 can go towards the hep V O

 

[Richard C]

Why would it need another vent though. I thought one was ok at the top of the stack?

Because you’re running two sanitary appliances into one pipe which is not good practice. Ideally you should have individual stack connections for each waste but even then there are maximum lengths for each size of waste pipe before you need to vent the branch. Usually emptying the bath will siphon the water from basin trap (but it can happen the other way around); air in the pipe is not replaced as the water flows down so it sucks it in through the weakest point which is the basin trap, pulling the water seal with it = gurgling; blip blip blip noises & drain smells.

Yh its 3inch 82mm so is a funny size to get a fitting for.

Yes, normal waste run is 40mm but high flow showers etc are 50mm; not sure if you will get an AAAV to fit 82mm, what size is the waste pipe from your basin trap?

 

[Richard C]

Bet it won`t - not dropping into a 3 inch - it`s not correct - but I`ll lay £5 it don`t syphon - if it does the £5 can go towards the hep V O

Maybe not with a 3” pipe; it’s unusual & I’ve only ever run 50mm max unvented but the OP also has two appliances on one pipe so it will also depend how much water is in the bath, how long the water flows & weather the basin trap is at the blind end or between the bath & the stack. If there was not previously a problem, I’m wondering why the end of the pipe has been left open, it must smell something orrible.

Perhaps OP should just cap it & see what happens ; if there is siphoning, fit a Hepvo to the basin.

 

[looneyfitter]

How long is that 3" run? id cap it off tbh. cant see you having any problems with it.

 

[tomsim]

It runs about 1.3meters to the bath and basin waste. And then another 1 meter or so to the open ended elbow. Would it be safer to fit a HepVo valve on the basin. I no I thought it was strange having an open ended pipe like this. Again thanks for all your help.

 

[looneyfitter]

cap it off mate, it will be fine.

If your worried, get a 3"x2" adapter and fit a 2" AAV at the open end

 

[tomsim]

Thanks for all your help. Can I just ask do these hepVo vales act as aav too? or are they just to stop syphonge?

 

[looneyfitter]

They will act as a trap and stop syphonage mate.

 

[tomsim]

Just one last quick check with you. On the picture the soil pipe extends through the house then in to the loft I think I can just see the dunut shape cowl coming out of the roof. If this wasnt connect anymore for what ever reason I will check in the loft tomorro. Could this be the reason for the open ended pipe am just wonderding why it was like this, open ended? Or would it not work as a vent for it as it's below the toilet and basin entry to the stack. Sorry I am just worried about capping it off.

 

[Richard C]

Duplicate post

 

[Richard C]

Bloody hell Loony your privileged that’s 2 to you, zilch to everyone else!